i 7 4 



ELEMENTARY ZOOLOGY 



attached to the wing 1 membranes ? How are the scales 

 arranged ? Note that the wing is colorless where the 

 scales have been removed. All the colors and patterns 

 of the wings of butterflies are produced by the scales. 



Make drawings of scales; of parts of denuded wings, 

 and of bit of wing covered with scales. 



Remove all or nearly all the scales from a wing and 

 note the arrangement of the veins (venation). Compare 

 with venation in wings of locust. 



Make drawing showing venation in the butterfly's 

 wings. 



The venation of insects' wings is much used in insect 



classification, and the 

 various veins have been 

 given names. The 

 names of the veins in 

 the butterfly's wings are 

 given in fig. 43. When 

 the veins in the wings 

 of all the various groups 

 of insects are studied, it 

 is evident that the prin- 

 cipal ones are the same 

 in all insects, so that 



FIG. 42-Bit of wing of monarch butterfly, the COSta, Sllb-CUSta, ra- 

 Anosia plexippus, magnified to show the dius, media, Cubitus and 



scales; some scales removed to show the 



anal veins of the butter- 



insertion-pits and their regular arrange- 

 ment. (From specimen.) fly's wings can be com- 

 pared with the corresponding veins in the wings of a 

 beetle or wasp or fly. Noting the differences in the num- 

 ber and character of branching of these principal veins, 

 and the number and disposition of the cross-veins which 

 connect the longitudinal veins, the various kinds of insects 

 can be to a large extent properly grouped or classified. 

 A detailed account of the wing-veins of insects is given 



